This invention relates to molded plastic liners for truck cargo beds and more particularly to a one-piece protective liner for a pick-up truck or the like.
Various truck bed liners have been disclosed in prior art patents. Examples of such liners are shown in U.S. Pat. No. 4,047,749 to Lambitz, et al., issued Sept. 13, 1977 and U.S. Pat. No. 4,111,481 to Nix, et al., issued Sept. 5, 1978. One problem with prior art truck liners concerns preventing moisture retention between the liner and the truck bed to reduce rusting and corrosion. Truck beds are particularly damaged by crevice corrosion which develops in localized areas because of small volumes of stagnant water trapped in surface depessions or corrugation troughs such as by clumps of mud. The condition is worsened where portions of the metal are covered such as by a truck bed liner.
A frequent trouble spot with prior art truck liners molded in one-piece is their lack of strength in critical bend and sidewall areas where impacting cargo may shorten the liner service life.
Another problem encountered in prior art molded truck bed liners is their inability to maintain proper conformance of the liner with the truck bed when heated since the plastic material has a tendency to distort causing the liner walls to develop bows or waves.
A further concern is providing a close fit between the truck bed and liner, such as the access opening corner areas, to prevent the entrance of water and dirt and to provide an aesthetically pleasing appearance.
It is thus an object of the present invention to provide a unitary molded truck liner having high strength for rugged durability while reducing moisture retention between the liner and the truck bed to minimize corrosion.
It is another object of the present invention to provide a one-piece truck bed liner having a ribbed construction that strengthens critical cargo impact areas while providing resistance to temperature induced distortion forces.